Special Counsel Mueller’s team just finished questioning one of the President’s associates considered so close to him that he’s known as the Trump “whisperer.”

Hedge fund mogul Tom Barrack has known Donald Trump for decades, ever since bailing him out of his 1990s business debacle. Significantly, Barrack served as the head of the Trump Inaugural Committee that took in a whopping $107 million but who kept their spending unusually secret.

Now, Mueller’s men had a lot of questions for the Trump Whisperer, whose deputy chairman on the Trump Inaugural Committee was none other than convicted former aide Rick Gates, who is cooperating with the probe. The APreports:

One of the people who spoke to AP said the questioning focused entirely on two officials from Trump’s campaign who have been indicted by Mueller: Trump’s former campaign chairman, Paul Manafort, and Manafort’s onetime deputy, Rick Gates. Gates agreed to plead guilty to federal conspiracy and false-statement charges in February and began cooperating with investigators.

A second person with knowledge of the Barrack interview said the questioning was broader, including financial matters about the campaign, the transition and Trump’s inauguration in January 2017.

Barrack’s representatives wouldn’t give comment on the matter to the AP.

Thomas Barrack was a top fundraiser for the Trump campaign, a speaker at the GOP Convention and a political advisor before he chaired the Trump Inaugural Committee.

Then, in January, journalists began to notice that the inaugural committee, which Thomas Barrack had chaired, possessed $50 million that wasn’t reportedly spent, and there were no public disclosures of where the money went. Of the $107 million Barrack raised, 91% came from only 250 very large donors.

A February tax filing showed that event planning firm owned by a friend of Melania Trump, and founded just to accept the payment, took in an unusual $26 million fee. The fee was unusual because events planning company Hargrove, which is on retainer to plan inaugurations, also got paid $25 million for essentially the same tasks.

President Trump has confided in Barrack for three decades, and he’s also been described as Trump’s power broker, so there’s really no limit to the information that he’s learned over that time.

There is no doubt that Thomas Barrack has a unique insight into Trump’s deeds and his mental state.

That’s why it is a very bad sign for President Trump that Mueller’s team is talking with the one man closest to him, who isn’t a blood relative.